Vitamin D

Alfacalcidol

Colecalciferol

• Cholecalciferol (vitamin D3)

  • Synthesized in the skin (stratum basale) when exposed to UV light

  • Fortified foods (e.g., milk, breakfast cereals, formula), fatty fish (liver), egg yolks, plants

• Hypocalcemia seconday to chronic renal failure

• Secondary hyperparathyroidism

• Hypo- and parahypoparathyroidism

• Nutritional rickets/osteomalacia

• Tetany in premature infants

• hypophosphatemia

• Hypercalcemia or evidence of vitamin D toxicity. 

• Known hypersensitivity to calcitriol, other vitamin D analogs, or any ingredient in the formulation. 

Excessive vitamin D intake (early manifestations): Weakness,  headache, somnolence,  nausea, dry mouth, constipation, muscle or bone pain, metallic taste,  anorexia, abdominal pain, epigastric distress. 

Excessive vitamin D intake (late manifestations): Polyuria, polydipsia, anorexia,  weight loss, nocturia,  calcific conjunctivitis,  pancreatitis, photophobia,  rhinorrhea,  pruritus,  hyperthermia, decreased libido, elevatedBUN, albuminuria, hypercholesterolemia, elevated AST,  elevated ALT, ectopic calcification,  nephrocalcinosis, hypertension, cardiac arrhythmias, dystrophy,sensory disturbances, dehydration, apathy, arrested growth,  urinary tract infections. 

• Synthetic vitamin D analog. 

• Calcitriol (activated vitamin D) enhances the efficiency of intestinal calcium absorption along the entire small intestine, but principally in the duodenum and jejunum.

• Enhances phosphorus absorption along the entire small intestine, but principally in the jejunum and ileum. 

• Calcitriol is the most active known form of vitamin D3 in stimulating intestinal calcium transport. 

• In patients with chronic renal failure, decreased metabolic activation of vitamin D in the kidneys results in secondary hyperparathyroidism and metabolic bone disease. [ref] In such patients, calcitriol increases GI absorption of calcium, decreases elevated blood concentrations of PTH and serum alkaline phosphatase, and corrects renal osteodystrophy, muscle weakness, and bone pain in such patients.